In Reply.—Dr Kopans suggests that the conclusions of our article on the PPV of screening mammography are biased and more sweeping than the data justify, and that we have targeted women younger than 50 years. In fact, we did not make a recommendation for or against screening average-risk women younger than 50 years. We concluded that efforts to promote screening mammography should focus on women 50 years of age or older and on women 40 years of age or older with a family history, in whom the majority of breast cancers occur (78% in our study) and in whom screening mammography has the highest PPV. We also recommended that all asymptomatic women who request or are offered screening mammography should be told the likely outcomes of screening. In addition, our article provides data about the performance of screening mammography that clinicians may use to inform women of likely outcomes